Portion of a display screen showing a user interface



The FIGURE is a front view showing the new design.

The broken line drawing of a portion of a display screen is for illustrative purposes only and forms no part of the claimed design. The broken line regions depicting a “+” and “>>” symbols on the two buttons form no part of the claimed design. The broken line depictions of “Content” are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a portion of a display screen showing a user interface, as shown and described. 